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Difficulty: HardNetwork Components Roles and Functions

An enterprise data center infrastructure deploys virtualized server hosts running Type 1 hypervisors. On a single physical host, multiple Virtual Machines (VMs) belong to different VLANs. Network monitoring reveals that intra-VLAN frame delivery between VMs on the host occurs locally without utilizing physical switch bandwidth, whereas inter-VLAN traffic between VMs on the same host must be forwarded out to an external Layer 3 gateway device. Which component operating within the hypervisor framework is responsible for performing local Layer 2 frame forwarding while enforcing VLAN isolation on the host?

  1. The internal virtual switch (vSwitch) provisioned within the hypervisor softwareAnswer
  2. B
    The host operating system kernel managing hosted workloads through a Type 2 hypervisor layer
  3. C
    The physical network interface card (pNIC) functioning as an unmanaged hardware device that terminates broadcast domains
  4. D
    The Link Layer Discovery Protocol (LLDP) management agent running inside the guest operating system

Answer

The internal virtual switch (vSwitch) provisioned within the hypervisor software is responsible for switching intra-VLAN frames locally on the physical host while leaving inter-VLAN forwarding to a Layer 3 routing boundary.
The internal virtual switch (vSwitch) operates at Layer 2 within the hypervisor software environment. It inspects Ethernet frame headers and MAC addresses to bridge traffic between virtual machines assigned to the same VLAN on the same physical host. Because it operates at Layer 2, frames destined for a different VLAN must be sent across a trunk link to a Layer 3 device (such as a router or L3 switch) for inter-VLAN routing.

Step-by-Step Solution

1
Analyze the operational requirements of host-internal VM communication.
Intra-VLAN traffic stays on the local host, while inter-VLAN traffic requires Layer 3 routing.
VLANs define separate broadcast domains at Layer 2. Passing traffic between different VLANs requires a routing decision.
2
Identify the software component inside a Type 1 hypervisor that handles Layer 2 frame forwarding.
The virtual switch (vSwitch) acts as a software-based Layer 2 switch connected to virtual network interface cards (vNICs) of virtual machines.
The vSwitch maintains MAC address tables per VLAN, enabling direct local frame delivery between VMs on the same VLAN without sending frames onto the physical network uplink.
3
Evaluate why inter-VLAN traffic must exit the host.
Standard Layer 2 virtual switches do not perform inter-VLAN routing unless a Layer 3 virtual router or external router interface is configured.
Without an integrated Layer 3 virtual router, inter-VLAN frames must be forwarded over physical uplinks to an external router or Layer 3 switch acting as the default gateway.

Key Concept

Hypervisor Virtual Switching and Traffic Isolation
Estimated Time:1m 30s
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Topics

Network Components Roles and Functions

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